A vertical conducting ring of radius R falls vertically with a speed v in a horizontal uniform magnetic field of induction B which is perpendicular to the plane of the ring. Then select the correct statement.

when the ring falls vertically there will be a potential difference across any two points on the ring if the line joining them has a projected length on horizontal plane. For the line PQ, projected length is x and the potential difference between P and Q is B.x.v. For points C and D, x = 0; hence, potential difference is zero. For points A and B, x = 2R; hence potential difference is B.2R.v.